1. Technical Field
The present invention relates generally to the manufacture of semiconductor devices, and more particularly, to the prevention of slurry build-up within low areas of a substrate topography during polishing.
2. Related Art
FIG. 1 illustrates a related art substrate 10 having topography, in this example, a low area 12. A first layer 14 is deposited over the substrate 10, coating the sidewalls 16 and bottom 17 of the low area 12. Prior to depositing a second layer, the substrate 10 is polished to remove the excess first layer 14 on the surface 18 of the substrate 10, leaving the first layer 14 only within the low area 12. However, the polishing material 20, typically slurry, used during the polishing step often fills the low area 12, as illustrated in FIG. 2.
In order to remove the polishing material 20 within the low area 12, harsh chemicals, such as HF, an Amonium Hydroxide HGL clean, (also known in the industry as xe2x80x9cWang ABxe2x80x9d), etc., are often required due to the strong mechanical bonds formed between the polishing material 20 and the first material 14 within the low area 12. These chemicals can permeate cracks in the substrate 10, and cause corrosion.
Accordingly, there is a need in the industry for a method that overcomes these and other problems.
The first general aspect of the present invention provides a method of preventing the build-up of polishing material within at least one low area of a substrate during polishing comprising: blanket depositing a first layer over the substrate; depositing a selectively removable material over the first layer, whereby the selectively removable material fills the at least one low area; polishing the substrate to remove the first layer and the selectively removable material from a surface of the substrate, leaving the first layer and the selectively removable material in the at least one low area; removing the selectively removable material from the at least one low area; and depositing a second layer over the substrate.
The second general aspect of the present invention provides a method of planarizing a substrate having at least one low area, comprising: depositing a first layer over the substrate; depositing a selectively removable material over the first layer; planarizing the substrate leaving the at least one low area, and the first layer and the selectively removable material within the at least one low area; and removing the selectively removable material from the low area.
The third general aspect of the present invention provides a method of planarizing a substrate comprising: depositing a selectively removable material within a low area of the substrate; planarizing a surface of the substrate; and removing the selectively removable material.
The fourth general aspect of the present invention provides a method of planarizing a substrate having at least one low area comprising: filling the low area with a selectively removable material prior to planarizing the substrate to prevent polishing material from building-up within the low area.
The foregoing and other features of the invention will be apparent from the following more particular description of the embodiments of the invention.